Method of constructing a wall and plastic window assembly



March 24, 1959 2,878,524

A- FlNK METHOD OF CONSTRUCTING A WALL AND PLASTIC WINDOW ASSEMBLY Filed April 9, 1954 INVENTOR flneo/v FINA ATTORNEY BYMW Aaron Fink, Maplewood,

METHOD OF CONSTRUCTINGA WALL AND PLASTIC WINDOW ASSEMBLY N.J., assiguor to Essex Paper Box Mfg. C0,, Inc., Essex County, N.J., a corporation of New Jersey Application April 9, 1954, Serial No. 422,131 3 Claims. (Cl. 18-59) The present invention relates to an assemblyof an apertured wall and plastic window; particularly of the type adapted for use with set-up cardboard boxes, display pieces and the like, and the method of making such an assembly.

The present art relating to boxes having transparent windows is limited to either completely flat, usually rectangular designs or more complex designs-of highly involved and costly construction. In either case, the process of manufacture includes a separate step of affixation of the window to'the box c'overlor' wall; such affixation being achieved by portions of the window, and other conventional fastening procedures. 1

An object of the present invention is to provide a wall and transparent plastic window assembly of simple and economical construction.

Another object thereof is the-provision of such an assembly capable of easy elaboration into forms which include windows of deep and complex design.

Still another object thereof is the provision of a highly efficient and effective method of producing assemblies.

These and other objects are achieved in the preferred form by the provision of a cardboard box cover having an apertured top wall in which is placed a transparent plastic window body of the desired shape, the sides of the window abutting the inner edges of the aperture in said wall conforming in shape thereto and bearing a peripheral indentation or groove formed therein in which the said edges rest, thus securing the window and wall. To obtain greater structural rigidity, the lower portions of said sides may be flared outwardly to form a continuous outstanding flange which abuts the inner faces of said wall.

The preferred method of constructing the wall and window assembly is to place the cover and a sheet of a thermoplastic material, such as cellulose acetate, in a vacuum mold, the walls of the mold adjacent the outer side of the aperture in the wall of said cover being slightly further apart than the corresponding edges of said aperture, apply heat and vacuum and permit the acetate sheet to assume the desired molded shape, then cool and remove the assembly. Here molding of the window and afiixation thereof to the wall will take place in one step.

Other objects and a fuller understanding of the present invention may be had by referring to the following detailed description and claims, taken in conjunction with the accompanying drawings which illustrate preferred embodiments thereof, it being understood that the foregoing statement of the objects of the invention and the brief summary thereof is intended to generally explain the same without limiting it in any manner.

Fig. l is an exploded view in perspective of a cardboard box cover and a sheet of acetate about to be placed therein in the first step of the process embodying the present invention.

Fig. 2 is an elevational section through a diagrammatic adhesives, strips secured over flanged such 2,878,524 Patented Mar. 24, 1959 representation of a vacuum mold employed in said process showing the acetate sheet before and after (in dot-dashed outline) the molding step.

Fig. 3 is an exploded perspective view of a box embodying the present invention. 1;

Fig. 4 .is a median elevational sectional view of the box of Fig. 3 in a closed state. 1

Fig. 5 is a perspective view of a box cover die cut to take a different shaped window.

Fig. 6 is another such view thereof with such a window.

Referring to the drawings and more particularly to the form of the present invention illustrated in Figs. 3 and 4, it comprises an uncovered box 10, having side walls 11 and a bottom wall 12, to which may be fitted a'cover13, having a top wall 14 and side walls 15, 16, 17 and 18; said top wall being rectangularly die cut to provide'an aperture 19, and a transparent window 20 extending, in this instance, a substantial distance out of the cover, and having a continuous bottom flange 21, there being an inward peripheral lateral groove 22 in the bottom margins of the sides thereof (i.e. at the junction of sides/and flange 21). v

The window may be made of a thin transparent plastic such as cellulose acetate. To assemble the cover 13, the window is merely pushed therein until the inner edges of aperture 19 are snapped into groove22. When this is done the top surfaces of flange 21 will abut the inner surfaces of top wall 14 of the cover. w

The lateral extent of flange 21 is not critical, butwithin reasonable limits the broader the flange the greater the structural rigidity of the window. This is especially important when thin sheets are used for the window of the order of perhaps 3 or 4 thousandths of an inch thick.

The method of assembly described is suitable where the window is preformed by any of the familiar molding processes. However, the present invention encompasses a new method of construction wherein the steps of molding the window and securing it to the cover or any other wall structure are coincident. Reference is made at this point to Figs. 1 and 2. Fig. 2 shows in schematic form a vacuum molding machine comprising a solid base 23, in which there has been formed a mold cavity 24 of the desired shape, there being in communication with said cavity air outlet tube 25 connected to a vacuum pump (not shown) which in the practical form is in communication with the cavity through a plurality of fine passages. The mold cover 26 is connected to base 23 by a hinge 27. Both mold cover and base may contain electrical heating elements respectively 28 and 29. Lugs 30 and 31 act as clamp members as hereinafter explained.

In assembling the window-wall unit, there is placed inside the cover 13 (see Fig. l) a sheet 32 of suitable thermoplastic material, such as cellulose acetate, of a thickness greater than that of the desired window thickness, said sheet being ortherwise dimensioned so as to approximate the inner dimensions of the cover. Said cover 13, with the sheet lying in it is put in the cavity mold of Fig. 2, as shown therein, the outside of the cover facing cavity 24. Mold cover 26 is then closed, lugs 30 and 31 abutting the entire width of said sheet over portions of the top wall of cover 13 adjacent side walls 15 and 17, respectively. For the sake of clarity, there have been omitted similar extended lugs depending from mold cover 26 which abut said sheet over portions of said top wall adjacent side walls 16 and 18. Hence by such or other clamp means sheet 32. is held over cavity 24, cover 13 acting as a gasket. The mouth of cavity 24 in said mold is of slightly greater width and breadth than aperture 19 in cover 13. Heating or resistance elements 28 and 29 may then operate to soften sheet 32 and the air in cavity 24 may then be evacuated through tube 25 to cause sheet 32 to assume the desired window shape. Of course, as a result of such a stretching" 19 in-cover 13 overhang the upper margins of cavity 24,

when the window is drawn, as shown in dot-dashed out- I :line in Fig. 2, the lateral peripheral groove 22 is formed directly about the inner edges of said aperture. By this means the window is securely afiixed to cover 13. Then, too, because such sections underlying lugs 30 and 31 and the other similar lugs not shown are held in place, they arenot materially afiected by the molding process (they may shrink a trifle) and they retain their original thickness. Such portions constitute flange 21. After cooling the assembly is removed. Of course, instead of a single cavity mold, one having multiple cavities could be used to assembled many windows and covers at one time.

While the molding .process described above is the vacuum process, the method of assembly may be used with other molding processes including air or other gaspressure molding, etc. Then, too, well known variations in the molding art are applicable. For instance, it may be desired:to preheat the acetate sheet by infrared heating panels, radiant heating panels, circulating hot air, or otherwise. .Or even drape forming may be used. The point here being,

made is that the present invention incorporates a process which is applicable to the conventional moldingprocedures and is not limited to the precise procedure of vacuum forming.

Figs. 5 and 6 have been included merely to demonstrate:

one of the many additional more complicated forms the Window may take. Here aperture 33 .in cover 13 is in the outline of a capped bottle and window 34 iszatridimensional portion of such capped bottle.

Although the present invention has been described with a certain degree of particularity, it is understood that the presentdisclosure has been made only by way of example mechanical molding employing hole-molds, being clamped against the margins of the mouth in suband that'numerous variations may be employed without transcending the scope of the invention as hereinafter claimed.

What is claimed is:

1. The method of mounting a plastic window to an apertured wall which comprises the steps of placing said wall against the margins of the mouth of a mold having acavity mouth larger than the aperture in said wall, placing a sheet of plastic material of larger dimensions than said aperture against said wall so as to abut the same on the side thereof opposite said mouth, deforming said sheet by differential fiuid pressure inwardly intothe mouth of said mold into contact with the walls of said mold, whereby a groove is formed in the molded plastic window thus formed, the walls of said groove embracing the margins of said aperture thus retaining said window in said wall.

2. The method of mounting a thermoplastic window toan apertured wall as described in claim 1, wherein said deforming of said sheet is eifected by first heating said sheet and then withdrawing at least some of the air from said mold.

3. The method of mounting a thermoplastic Window to an apertured wall as described in claim 1, said sheet stantially air-tight relationship thereto prior to the heating of said sheet.

References Cited in the file of this patent UNITED STATES PATENTS 2,345,112 Grundel Mar. 29, 1944 2,367,642 I Helwig Jan. 16, 1945 2,591,276 Middleton Apr. 1 1 952 2,607,082 Starke Aug. 19, 1952 2,655,260 Clerc Oct. 13, 1953 2,697,057 Senger et al Dec. 14, 1954 2,694,227 Fordyce at 211.; Nov. 16, 1954 FOREIGN PATENTS 669,240 France Nov. 13, 1929 

